# air-purifier

A small 3D-printed desktop air purifier: a PETG body and lofted inlet, 90 mm PC fans run from USB, and an off-the-shelf pleated paper filter.

## Overview

This project is a small desktop air purifier built around a printed enclosure. The enclosure is split into two parts: a body, which serves as the main housing, and an inlet that mounts to the body. The inlet is a lofted part that shapes the path air takes into the purifier. Air is moved by 90 mm desktop PC fans powered over USB, and it is filtered by a Briggs & Stratton 593260 air filter, the oval pleated paper filter sold for small engines.

## How it works

The design has two parts:

| Part | Description |
| --- | --- |
| Body | The main housing of the air purifier. The inlet mounts to it. |
| Inlet | A lofted part that forms the air intake. It was modeled in Fusion and exported as STEP and STL. |

The parts have been printed in PETG.

### Fans and power

The fans are 90 mm desktop PC fans. They are powered over USB: the USB leads are wired in series, so the fans see about 10 V instead of a 12 V supply.

### Filter

Filtration is done by a Briggs & Stratton 593260 air filter, the oval pleated paper filter. It is a common replacement part, so it is easy to find and swap.

## Status

Revision o1.0A is the first revision. It provides CAD for the body and the inlet, and the parts have been printed in PETG. Current revision: **o1.0A**.

Photos of the printed o1.0A unit are in `o1.0A/photos/` (full size), with web copies in `o1.0A/photos/web/` and thumbnails in `o1.0A/photos/thumb/`.

## Build and use

What you need:

- The printed body and inlet, in PETG
- 90 mm desktop PC fans
- USB leads, wired in series to supply about 10 V to the fans
- A Briggs & Stratton 593260 air filter (oval pleated paper)

Files in this revision:

- `body-o1.0A.step`: body (STEP)
- `inlet-o1.0A.step`: inlet (STEP)
- `inlet-o1.0A.stl`: inlet (STL, ready to slice)

1. Print the inlet from `inlet-o1.0A.stl`, or export an STL from the STEP file.
2. Export the body from `body-o1.0A.step` to a mesh and print it.
3. The parts have been printed in PETG.
4. Mount the inlet to the body.
5. Fit the fans and wire their USB leads in series.
6. Fit the Briggs & Stratton 593260 filter.

## Known limits

- Airflow and CADR (clean air delivery rate) have not been measured.
- Filtration performance has not been tested. The 593260 is an engine intake filter, not a rated HEPA filter, and no particle capture figures exist for this build.
- Running 12 V PC fans at about 10 V from USB means they spin slower than their rated speed and move less air than their spec sheets state.
- The body is provided as STEP only. You need to export your own mesh from `body-o1.0A.step` before slicing it.

## Revisions

- **o1.0A** (current): First revision: body and lofted inlet in STEP, inlet also in STL, printed in PETG, 90 mm PC fans on series-wired USB (about 10 V), Briggs & Stratton 593260 filter.

Revision codes read o (open) or c (closed), then major.minor, then the branch letter; A is the main line.

## License

PolyForm Noncommercial License 1.0.0. See [LICENSE](Legal/LICENSE).